Preheat your oven to 425°F (220°C) and line a baking sheet with parchment paper.
Season the 4 oz chicken breast with salt, pepper, a squeeze of lemon juice, and finely chopped fresh herbs. For a crispy finish, lightly spray or brush with a small amount of olive oil.
Place the chicken on the baking sheet and bake for about 18-20 minutes, turning halfway through, until the chicken is golden and cooked through.
While the chicken is baking, prepare the salad by combining mixed greens, halved cherry tomatoes, cucumber slices, and thinly sliced red onion in a large bowl.
In a small bowl, whisk together the remaining olive oil, lemon juice, and additional fresh herbs if desired, and season with salt and pepper.
Once the chicken is done, let it rest for a few minutes, then slice it into bite-sized pieces.
Toss the salad with the dressing, top with the sliced crispy chicken, and serve immediately.